Filter panel



0. H. SCHAAF Sept. 4, 1951 FILTER PANEL Filed July 11, 1947 FIG.1

- uvmvrox. QUVER H.5CHAAF' ATTORNEYS.

Patented Sept. 4, 1.951

UNITED STATES PATENT OFFICE Oliver H. Schaaf, Shaker Heights, Ohio, assigiior to Air-Maze Corporation, Cleveland, Ohio, a

corporation of Delaware Application July 11, 1947, Serial No. 760,320

1 Claims; (Cl. 18369) I This invention relatesto improvements in a filter panel for filtering particles out of a gaseous stream.

One of the objects of the present invention is to provide a filter panel formed of strips of screen mesh material which may be cheaply manufactured in continuous lengths 'and cut and "assem bled in a filter frame as disclosed hereinafter.

Another object of the present invention is to provide a filter panel of the type described having passageways extending uninterruptedly from front to rear of the panel for the free passage of air in case the panel becomes clogged with dirt but the passageways being so constructed and arranged that normally the air stream or gas stream cannot pass directly through the same.

Another object of the present invention is to provide a filter panel each layer of which is provided with a zig-zag crimp, of 2 form, which provides one advantage that the strip of screen mesh material will pass through a crimping roller without tendency to move out of a straight line and with the second advantage that the crimps placed relatively close to the front and rear edges of a given layer of material aid in the holding of the filaments of the screen mesh along the edges so as to prevent ravelling.

Still another object of the present invention is to provide a filter panel comprising a plurality of layers of screen mesh material provided with corrugations in 2 form, with the meshes of adjacent layers reversed, so that a plurality of fila ments near each edge of the filter panel are in close juxtaposition so as to hold a liquid adhesive material such as oil between the filaments.

Other objects and advantages of my invention will be apparent from the accompanying drawings and description and the essential featuies of the same will be set forth in the appended claims V in the drawings, H V n I Fig. i is a front elevational view of a filter panel embodying my invention with a portion of the front protective screen broken away to more clearly show the constructions V Fig. 2 is a transverse sectional view greatly enlarged taken along the line 22 of Fig. 1;

Fig. Bis a diagrammatic view illustrating some of the details involved in the layout of an individual layer of filter material; while Fig. 4 is an end view of the same taken approximately from the position 4-4 of Fig. 3 and enlarged and exaggerated to illustrate the point.

One form of my invention is shown in Figs. 1 and 2 and comprises a main frame Ill which is of channel form having webs lfla parallel to thedirection of stream now and having edge flanges lilb overlying the edges of the filter element around the entire periphery of the panel as clearly shown in a fragmentary view in Fig. 2. Itwill' be noted that the front and rear faces of the pane1 are opened for air flow in the direction of the arrows of Fig. 2. I perfer to form my filter element of screen mesh material of the order of sixteen meshes er inch similar to ordinary fi'y screen although it will be understood that other types of stiff mesh material might be used to carryout my invention. I prefer to form my filter elements by cutting the screen mesh material into elongated strips under two inches in width in one form of my invention althought of course this dimension may be varied according to the thickness of the filter panel to be formed. These elongated strips of screen material are passed between corrugated crimping rolls to provide corrugations of 2 form as shown in Figs. 2 and 3.

In one form of my invention the dimension A measured at right angles to the corrugations is three-eighths of an inch between adjacent ridges. This makes the dimension B at right angles to the general direction of stream fiow approximate-- ly seven-sixteenths of an inch. In one form of my invention, the dimension J of Fig. 4 is approximately three-sixteenths of an inch and the form of corrugation is approximately as shown there. Referring now to Fig. 3 in one perferredform of my invention the dimensions C is threeeighths of an inch and the dimension D is one inch. At the same time, the angle E is at an angle of approximately thirty degrees to the general direction of stream iiow through the panel. At the point of first change in direction of the crimp or corrugation the angle F is approximately one-hundred and twenty degrees. At the next reversal of crimp direction the angle G is approximately one-hundred and twenty degrees and the angle H is again approximately thirty degrees from the direction of air flow through the panel. While Variations may be made from the dimensions and angles just mentioned, it is desirable that they be so chosen that there is no possibility of the direct passage of particles through the filter panel along a line between adjacent crimps such as the line K which is a dotted line in Fig. 3. It should be noted here that the full zig-zag lines represent the theoretical direction of the ridges of the corrugations whereas actually the true crests of the ridges are of curved form, as clearly shown in Fig. 4, and prevent a direct path through a single corrugation along any line similar to K.

After the strip of screen mesh material are.

corrugated as above described, they are then cut to proper length to fit within the frame It]. As illustrated in Fig. 2, if the corrugations of the layer II are bent in one direction then the corrugatlons of the next layer l2 are reversed and the corrugations of the next layer I3 again extend in the same direction as those of the layer II. I may either form the layers H and I3 in one machine and the layers I2 in another machine or strips formed as in the layer H may be reversed in position to form the layer such a l2. It will be noted that the layers as placed in the filter panel permit air flow from front to rear of the panel generally parallel to the direction of the extension of corrugations. In other words, the stream fiow is generally parallel to the screen rather than through the screen. When the filter panel has been filled with the screen layers, preferably but not necessarily, a front and rear protecting screen M and I5 is provided which may be of coarse hardware cloth, expanded metal, or other suitable protective and strong material.

Preferably, adjacent layers are so arranged that adjacent corrugations cross each other as shown in the mid portion of Fig. 2. Here the uppermost ridges of each layer nearest the observer are shown in the heavier lines. These ridges for the layer l3 are shown in broken lines beneath the layer l2. It will be noted that the .short portions 12a of the corrugations of the .layer 12 which form troughs (shown in lighter .line) are in crossing relation with the portions ,lta of the ridge of the layer ll directly be- :neath. Because each ridge and trough has a .somewhat flattened form as shown in Fig. 4 a number of wire filaments are thus brought into dlrect contact or into sufficiently close contact so that when the filter panel is coated with adhesive material, such as the oil commonly used, little reservoirs of this oil are formed between the filaments which touch or almost touch at the front and rear face of the panel. This greatly aids the dust holding capacity of the filter.

One of the difllculties which has occurred in the construction of filter panels of assembled screen layers having zig-zag corrugations therein, has been a tendency of the strips of screen material to travel to one side when passing through the crimping rolls. In the present design thls has been overcome because in passing through the crimping rolls the portions 16 and I'Ia (Fig. 3) provide equal tendencies to pull the strip toward the right and left and therefore counterbalance each other. Likewise, the portions Nb and it have a similar effect. The net result of the entire construction is that the elongated trips pass through the corrugating rolls Without any tendency to move toward the right or left.

Another disadvantage of previous filter elements constructed similar to mine, has been a tendency of the edge filaments to ravel at the .front and rear faces of the filter panel. The arrangement of my Z form corrugations overcomes this dimculty which I have endeavored to illustrate in Fig. 4. The wire l8a extending crosswiseof the strip of screen mesh material coming downwardly across the portion ill of the corrugation have a tendency to continue downwardly as shown in Fig. 4. The wires 18b on the opposite side of the corrugation, due to the angle G, have a tendency to extend upwardly as shown in Fig. 4. It results from this construction that the edge filament 20 extending longitudinally of the strip is held in position and does not ravel easily.

The operation of my improved filter panel should now be apparent. When an air or other gaseous stream fiows through the panel in the direction of the arrows of Fig. 2, particles collect on the adhesive coated Wires as the stream Works itself from the front to the rear face of the panel through the maze of wires. There is practically no tendency for the gaseous stream to fiow directly in the 2 hape passageways between adjacent corrugations, at least until the walls of the corrugations have become so coated with particles as to force this type of flow. Obviously, when this occurs it is time to clean the panel. It will be noted from Fig. 2 that the corrugations of the layer I2 are in direct contact with the corrugations of the layers ll but in. crossing relationship. Thi creates a turbulence a the stream passes through the panel and increases its efiiclency. It should be apparent to those skilled in this art that my panel has very low resistance to the passage of a gaseous stream and has a very high dirt holding capacity.

While the above description has been devoted to the collection of solid particles, it should be understood that my improved filter panel may also be used to remove liquid particles from a gaseous stream.

Filters of this general type are known to me having no bend 01' one bend between the front and rear face of the panel. It is possible for stream-borne particles to pass straight through the no bend device or through a single layer of screen and then straight through the one bend device. In my two-bend arrangement or Z form of corrugation, a particle starting down one corrugation and continuing in a straight line must pass through several layers of screen before finding a passageway leading to the opposite face of the panel.

What I claim is:

1. A filter panel for placement in a fluid stream and comprising a plurality of generally parallel contiguous foraminous mesh screens extending in the general direction of stream flow, each of said screens being provided with parallel corrugations generally Z form in plan, the corrugations of one screen crossing the corrugations of adjacent screens in crossed relation, and frame means for causing a fluid stream so to flow.

2. A filter panel for placement in a fluid stream and comprlslng a plurality of generally parallel contiguous foraminous mesh screens extending in the general direction of stream flow, each of said screens being provided with parallel corrugations generally 2 form in plan, the corrugations of one screen crossing the corrugations of adjacent screens in crossed relation, the middle leg of the Z form being longer than each of the end legs of said 2 form, and frame means for causing a fluid stream so to flow.

3. A filter panel for placement in a fluid stream and comprising a plurality of generally parallel contiguous foraminous mesh screens extending in the general direction of stream flow, each of said screens being provided with parallel corrugations generally 2 form in plan, the corrugations of one screen crossing the corrugations of adjacent screens in crossed relation, the middle leg of said Z form being of the order of twice as long as each of the end legs of said ,stream and comprising a plurality of generally parallel contiguous roraminous mesh screens extending in the general direction of stream flow,

each of said screens being provided with parallel corrugations generally 2 form in plan, the corrugations of one screen crossing the corrugations of adjacent screens in crossed relation, the middle leg of said Z form being of the order of twice as long as each of the end legs of said 2 form, the angle between the middle leg of said Z form and each of the end legs thereof being of the order of one hundred and twenty degrees, and frame means for causing a fluid stream so to flow.

5. The combination of claim 1 wherein the 8 angle between the legs of said Z form and the extent of said legs is such as to block a clear straight passage through a single corrugation of one screen fromone side of said panel to the other.

OLIVER H. SCHAAF.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Numb-er Name Date 1,734,125 Greene Nov. 5, 1929 2,190,886 Schaaf et al Feb. 20, 1940 2,286,479 Farr June 16, 1942 2,478,097 Glanzer Aug. 2, 1949 

